This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Introduction: Functional magnetic resonance imaging (fMRI) studies have shown evidence of aberrant neural activity when individuals with fragile X syndrome (FraX) perform executive function tasks. Specific Aims: To investigate the specific nature of this aberrant activity or possible compensatory processes that has yet to be elucidated. Methods: We examined brain activation patterns using fMRI during a go/nogo task in adolescent males with FraX and in controls.